Footed dolphins

ABSTRACT

A dolphin structure is provided in which the overturning moment about the seabed, due to horizontal loading at the upper end, is counteracted by the moment of the dolphin self-weight about its points of support. The dolphin is comprised of a vertical stem supported on the bottom by laterally extending elongate toes which in effect act as a foot upon which the dolphin is balanced. These extensions are similar in structure to the dolphin stem and may be two or more in number. The extensions are rigidly connected to the stem, typically by welding, but alternatively by bolting or other means. The extensions are deployed at various azimuthal angles depending upon the range of directions of horizontal forces anticipated to be applied at the upper end of the dolphin. Embedment in the seabed thus is obviated. The relationship between applied load and horizontal deflection of the loading point is bi-linear and the dolphin is able to absorb far more energy than is associated with the elastic distortion of its component parts.

iJn-ited States Patent 11 1 Holley, Jr.

[ 51 Sept. 16, 1975 l 1 F ()OTED DOLPHINS Myle .l. Holley, Jr-, 1364 Massachusetts Ave., Lexington, Mass. 02173 221 Filed: Jan.7, 1974 211 Appl. No.: 431,456

[76] Inventor:

[52] US. Cl.. 61/46; 1 14/219 [51] Int. C13... E02B 3/22 [58} Field of Search 61/46, 48; 114/230, .5 BD,

Primary ExaminerPaul R. Gilliam Assistant Examiner-Alex Grosz Almnit'y, Agenl. 0r Firm-R. S. Sciascia; C. E. Vautrain, Jr.

[ 5 7 1 2 ABSTRACT A dolphin structure is provided in which the overturning moment about the seabed, due to horizontal loading at the upper end, is counteracted by the moment of the dolphin self-weight about its points of support. The dolphin is comprised of a vertical stem supported on the bottom by laterally extending elongate toes which in effect act as a foot upon which the dolphin is balanced. These extensions are similar in structure to the dolphin stem and may be two or more in number. The extensions are rigidly connected to the stem, typi' cally by welding, but alternatively by bolting or other means. The extensions are deployed at various azimuthal angles depending upon the range of directions of horizontal forces anticipated to be applied at the upper end of the dolphin. Embedment in the seabed thus is obviated. The relationship between applied load and horizontal deflection of the loading point is bi-linear and the dolphin is able to absorb far more energy than is associated with the elastic distortion of its component parts.

14 Claims, 8 Drawing Figures 1 I FOOTEDDOLPIIINS The invention described herein may be manufactured and used by or for the Government of theUnited States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention concerns dolphin structuresand, moreparticularly, a dolphin which is provided with a foot-like appendage upon whichit is supported on the bottom. A i r '1 In conventional dolphins, comprised of one or more piles embedded in the seabed, the overturning moment energy, in the process of reducing the transverse velocity of a contacting ship. Thus it is highly desirable to maximizc'the energy absorbing capability of a dolphin while minimizing the ship-to-dolphin contact forceI These objectives require maximization of the horizon- .tal'displacement of the point of loading at the top of the dolphin, corresponding to each value of the applied load. In conventional dolphins the displacement of the loading'point is limited by the strength of the dolphin material and/or by the capability of the seabed soil to withstand repeated stress without irrecoverable deformations.

The present invention provides a capability for lateral displacement of the point of loading which is greatly in excess of the displacement capability of a conventional dolphin. Moreover, for dolphins encompassed by the present invention, the average magnitude of the applied load is a larger fraction of the maximum magnitude of the applied load than is true ofa conventional dolphin. These two characteristics, larger displacement capability and larger ratio of average to maximum load,'cause the energy-absorbing capacity of a dolphin er the present invention to greatly exceed the energy-absorbing capacity of a conventional dolphin for equal values of maximum ship-to-dolphin contact force. The presentinvention, in general, concerns dolphins in which thesingle or multiple piles of a conventional dolphin are'replaced by a'single or multiple element vertical dolphin member or stem provided with footlilte appendages or extensions for transmitting forces to the seabed. Forces applied at the top'of the dolphin stem cause bending of the stem and the base'extensions of the footed dolphin. The footed dolphin delivers ver= tieal upward forces'tothe seabed only in the rare event of an extreme. accidental, dolphin overload. In such 'a case, lift=off of the ends of the base horizontal exten= sions may cause a displacement limiting hold=down member to be engaged thus developing a vertical up= ward force in the seabed of relatively small magnitude. extensions are substantially identical in form and structure to the vertical member or members and maybe two or'more in number deployed atselected an= gles depending upon the horizontal forces expected to he applied against the dolphin at the waters surface.

Accordingly, it is an object of the present invention to provide a dolphin structure which does not apply any I points.

It is another object of this invention to provide a dolphin structure which; need. not penetrate thebottom and .is adapted to any kind of bottom.

. It is a further object of this invention to provide adol; phin structure which may be varied in the lengths. of its base support members ,to provide acounter-balancing V moment of suffi cient magnitude to off-set horizontal loading of the structure.

Other objects, advantages novel features of the invention will become apparent from the follow ing detailed description whenconsidered in conjunction with the accompanying drawings in which like numerals represent like parts throughout and wherein:

FIG. 1 is a perspective view of one embodiment of a dolphin structure made according to the teachings of this invention in use; i v

FIG. 2 is a perspective yiew of an alternate embodiment of the invention in position for use;

FIG. 3 is a diagram indicating response of the embodiment of FIG. I to a horizontal loading at the waters surface; v 7 Y L FIG. 4 is a side elevation of means for supporting and guiding therlateral base extensions of-the dolphin structure on a rock bottom{ FIG. 5 is a side elevation of alternatemeans for sup porting and guiding the lateral base extensions of the dolphin structure; i

FIGS. 6 and 7 areelevations' of alternate means" for supporting and guiding the lateral base'fextensions of the dolphin structure; and v L 1 FIG. 8 is a plan view of the supporting means of FIGS. 6 and 7.

The present invention provides a dolphin structure that delivers virtually no moments to the seabed at any of the individual support points of the structure. A bilinear, force-displacement response is an important feature of the invention. An initial, elastic response occurs which reflects displacement of the dolphin struc ture resulting from bending of the vertical member and of the horizontal base extensions affixed to the vertical member. In this range of response, bending of the horizontal extensions contributessignificantly to the displacement of the top of the vertical member thereby increasing the energy that can be absorbed by the doI-- phin structure. r

At apredet'e'rmined magnitude of applied loading, lift off occurs at the outboard end of the horizontal extensions substantiallydirectlybeneath the load applying force. Thereafter, the applied load ean'notincrease and, intact, the loading decreases slightly in proportion to further displacementof the top of the vertical memher. This precludes the developing'of bending stresses in the extensions in excess of their design values. During the second or lift-off phase of the forcedisplacement responscfthe point of applied loading. i.e.' at the top of the vertical member, can accept very large displacement at gradually decreasing loads thereby absorbing very largemoments of energy. In contrast, conventionaldolphins. comprised of one or more piles driven into the seabed cannot develop this bi=linear force=displacement response except by yieldingof the dolphin material and/or by irrecoverable displacement in the soil,the yielding permanent damage and threat of fracture. The components of the footed or pedestal dolphin do not have to be'tubular nor made of steel. Steel tubes, however, are preferred because they can be filled with sand, concrete, or other suitable substance thereby incteasing the weight of thecomposite structure and decreasing the length'of the horizontal extensions required to provide'the desired loading ca paci'ty. The use of steel tubes also facilitates on-sho're fabrication and towing of the structure in a floating modeto the site"of the installation. "At the site; the structure may first be sunk and then sand filled by pumping where this method can be accomplishedeconomically.

Where the seabed is rockyoi' otherwise unsuitable for pile drivingithe' invention can'provide a dolphin in an area where conventional dolphins are not possible. Since the ratio in pedestal dolphins of horizontal force to be transmitted to'the seabed to vertical force supplied by the net buoyant weight of the dolphin typically is less than twothirds, and for most directions of applied loading is less than one-half, only minor preparation, if any, of the rock surface is required to provide the necessary horizontal force transfer capability.

Referring now to the drawings, H6. 1 illustrates the pedestal or footed dolphin in operation, that is with a horizontal load applied at the'surface of the water by vessel 11. A dolphin structure 12 receives the load at the water surface and distributes the load through bending ofa vertical stem member 13 and base extensions l6, 1"), and 18 thereof. Where the energy to be a bsorbedaexceeds a preselected amount, this excess may cause a further displacement of the structure in the direction of load application and a tilting of the dolphjn. Dolphin 12 in the inoperative condition rests en tirely upon the bottom of the body of water in indirect contact therewith through pads 21, 22, and 23, respectively. Thesepads have a selected surfacearea sufficient to distribute theweight of the dolphin structure onthe bottom plus additional forces supplied when the dolphin is loaded and overloaded by horizontal forces. Pads 211-23 in the.type of penetrable bottom shown in FIG. {preferably are each provided with a short pile 25,which is shown at pad 23 only, of selected length to-assure that. the pads remain virtually immovable in the bottom. Each pad is further provided with guide horizontal displacementof some of the base extensions,

16 and 17 in this instance, is arrested by cross bars and 31 intercepting .the vertical rods 26 most remote from the applied force. A further overload causes the entire structure to be tilted, lifting the base extension most directly beneath .the loading force off of its pedesml. The base extensions are sufficiently long. typically 50% to 60% of the length of the vertical stem member. to provide a considerable counter moment to the moment of the loading force. The extensions and the vertical member may be additionally'weighted with sand or concrete. increasing the resistance to lifting of extension l8, in this instance, in the caseofextrcme overload.

It will be appreciated that in cases of an extreme force being applied to the structure such as by winds of hurricane force drivingship ll, against the vertical membenthat member will sustain extreme bending beforethe dolphin structure is overturned. Thus, in all cases except where the extreme forces of nature occur or the contacting ship is out of .control the structure in overload will act as shown in FlG. l, i.e. a minor lateral movement of some of the baseextensions and lifting of the other extension or extensions off of their pads. Upon release or dimishment .of the horizontal loading force, the structure will return to its normal posture, in this case a 3 point support with vertical rods 26 serving to center extension 18 on pad 23.

FIG. 2 ,illustrates an alternate embodiment of the invention which also has a 3 point stance but in which loading forces are anticipated only from the direction indicated by arrow 35 so that only a pair of base extensions 37 and 38 are required. Support pads for the base of a vertical stem member 39 and extensions 37 and 38 are shown at 40 and 41 with pad 40 in this particular embodiment being provided with a single guide rod 43 whose primary function is to limit the lateral movement of the structure. The pads for the base extensions may be provided with simple U-shaped brackets as indicated at 44 which also limit lateral movement and additionally serve to limit the vertical displacement at the extensions. Brackets 44 do not limit the flexibility of the structure since loading is applied only in the general direction-indicated by arrow 35. The extensions in this embodiment conceivably would not be lifted off of their respective pads. In the extreme case. however, of a ship being secured to vertical member 39 and. an unexpected force applied to the ship such as a strong wind in the direction indicated at 45, brackets 44 would become effective in limiting the response to such an abnormal loading force.

FIG. 3 illustrates the effect of a horizontal loading force applied at the surface of the water against a vertical stem member represented by line 50. At a predetermined magnitude of the force, F, the base extensions represented by 51 and 52 will lift off of their support pads on the side from which the force F is applied as indicated at 54. Thereafter P will remain essentially constant under further displacement since the overturning effect of F is counterbalanced by the righting force associated with the dolphin weight, W. Weight W is comprised of the net of the dead weight minus the buoyancy of the lower portion of vertical member 50 and the base extensions.

It will be appreciated that in some embodiments the support pads may be dispensed with if the bottom is firm enough to support the dolphin structure at or near itssurface. Such a bottom necessarily would also restrict horizontal displacement of the dolphin due to horizontal loading caused by vessels or, waves as well as horizontal displacement caused by tides and vessel wake.

FIG. 4 illustrates a concrete pedestal 57 which may be used on a rockybottom such as indicated at 58 on which sand, silt or clay is indicated at 59 may have ac= cumulatcd. if considered necessary, extensive lateral displacement of the structure may be limited by means secured to the pad 57 such as brackets 60 and 61.

FIGS. 2 and 5 illustrate means for limiting upward movement of the ends of a horizontal extension of the dolphin structure when the extension has lifted off of its support. Horizontal movement normalto the base extensions necessarily is limited to'prevent excessive lateral displacement of the extensions under the exceptional circumstance of concurrent lift-off of two extensions of a dolphin structure having three base support points. As indicated previously, vertical displacement of the ends of the base extensions requires limitation only in the case of unforeseen extrodinary horizontal loading forces which might otherwise overturn the dolphin structure. The support in FIG. 5 includes a pad 63, a pair of brackets 64 and 65 to guide a base extension 66 back onto pad 63 after lift-off, and a chain or other flexible connector of suitable strength 67 to restrain vertical displacement where this is considered essential in this support embodiment. Base extension 66 is provided with a short bearing piece 68 having a spherical contour 69 while the support pad 63 has a spherical seat 70 formed therein which serves to induce the dolphin structure into a centered stance upon removal of the loading force.

The supporting means illustrated in FIG. 6 is suitable in those locations where a guide pile 74 may be readily driven into the bottom. In such an arrangement, a base extension 75 of the dolphin structure is cut away on opposite sides, i.e. at 76 and 77, to accommodate in free movement guide pile 74. Baseextension 75 will also have attached to it preferably by welding a pair of diaphragm plates 78 and 79 which conform to the curvature of the extension of their upper surface and have a straight lower surface which conforms to the surface of a support flange indicated at 80. It will be appreciated thatflange 80 may have a greater or less area for weight distribution on the bottom dependingon the consistency of the bottom. In this embodiment, therefore, guide pile 74 penetrates base extension 75 and flange 80 between two diaphragm plates and is stationary during vertical displacement of base extension 75.

An alternate use of a guide pile is illustrated inFlGS. 7 and 8. In this arrangement, a sleeve tube 84 having an inner diameter substantially greater than the outer diameter of a guide pile 85 is welded to a base extension 86. A bottom support in the form of a flange 87 is cut away to permit free movement therethrough of guide pile 85. Sleeve tube 84 extends through extension 86 and has a planar end surface which circumferentially contacts a support flange 87. Where it is desired to impose a limit to the upward movement of base ex-. tensions on guide tubes, a stop 88 may be welded or otherwise secured to those guide tubes. The embodiments of FIGS. 6-8, as previously stated, are used when the seabed is suitable for receiving driven piles. In such arrangements, the dolphin structure may first be positioned on the seabed and thereafter the guide piles can be driven through either the sleeve tube or the openings in the base extension. Flanges 80 and 87 and sleeve tube 84 may be assembled and welded to extensions 75 and 86, respectively, prior to lowering these dolphin structures into position. Of course, the guide piles may extend any desired distance above the seabed to accommodate the anticipated lift-off base extensions under any anticipated set of circumstances, subject only to limits associated with'water depth and ship drafts.

The present invention thus provides a gravity balanced dolphin which rests upon the bottom yet absorbs of the top of the vertical member thereby increasing the 'energy absorbed by the dolphin. At a predetermined magnitude of the loading, liftoff occurs at the remote ends of one of the horizontal extensions or at the base of the dolphin stem in a dolphin having only two horizontal extensions. Thereafter, the loading ac? cepted by the dolphin structure cannot increase and, in fact, decreases slightly in proportion to further displacement of the vertical member. This characteristic precludes the development of bending stresses in the dolphin members in excess of design values.

During the subsequent phase of the forcedisplacement response, that is after lift-off, the point of applied loading at the top of the vertical member can accept a very large displacement under a gradually decreasing load thereby absorbing very large amounts of energy. In contrast, a conventional dolphin, i. e. a do] phin comprised of one or more piles driven into the seabed, cannot exhibit this bi-linear force-displacement response except by yielding ofithe dolphin material which implies permanent damage to and threat of fracture of the material, and/or by yielding of the soil was ing irrecoverable displacements. l

The footed dolphin alternates forces at the bottom of a type that are transferred into the bottom by conventional dolphins. However, the alternation process results in virtually no moments being delivered to the seabed at any of the dolphin support points. Additionally, no vertical upward forces are delivered to the points of seabed loadingexcept in the rare event of extreme overload. in such an event; lift-off at one or more points of dolphin support may cause therestraining hold-down means associated with such support points to be engaged. This action will develop a vertical, up ward force of limited magnitude on the seabed. For many installations, however, a hold-down means is not required because horizontal displacement of the top of the vertical member sufficient to threaten overturning of the dolphin would only occur under conditions judged to be incredible. Under such conditions, no vertical upward force can be imposed on the seabed.

The components or structural members of the pedestal dolphin need not be tubular nor need they be made of steel. Steel tubes, however, are desirable because they are readily available and can be filled with sand or concrete thereby increasing the weight to be displaced and decreasing the length of the horizontal base extensions required to provide the desired loading capacity.

Where the seabed is not suitable for pile driving, such as in areas having a rock bottom, the present invention is particularly useful since only minor penetration of the rock surface, if any, is required to provide the necessary horizontal force transfer capability.

When the pedestal dolphin is subjected to forces over only a limited range of horizontal directions, eg. when it is used for ship berthing manuvers. the horizontal base extensions may be made of differing lengths and angular spacings appropriate to the specific application. There are even cases where one of the three horizontal extensions can be eliminated. leaving the dolphin supported at the end of the remaining two extensions and the junction of those two extensions with the vertical member.

In all embodiments, some upward displacement of the end of each horizontal extension must be permitted, while for many applications such upward displacement need not be limited in any way. Horizontal displacement normal to the base extensions can be accepted where the extension is guided back down onto the support. The restraint to horizontal movement can be rigid guides spaced sufficiently apart to provide a substantial clearance for the base extension between each set of guides. The restraint to vertical movement can be an inverted U-bar or a slack chain secured to the support base under the extension. A leg or key preferably is attached to the bottom of the support for transmittal of horizontal forces. Such forces can be transmitted simply by a spherical protuberance on the bottom of the extension which engages a cavity in the support pad.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. For example in situations where no contact between the lower hull, e.g. the chine, of the vessel and the vertical stem member is desired, and the dolphin need accept vessel contact from one general direction only, the stem member may be inclined toward approaching vessels in such an amount as to be displaced to a substantially vertical position under full horizontal loading by a vessel. Bending and other energy absorption occurs in all dolphin members as in the illustrated embodiments. However, it is considered preferable to attach fendering to the inclined stem in lieu of suspending fendering from the vessel. Additionally, the inclined dolphin stem may have a single base extension secured to it, extending in the plane of the stem, provided the extension is suitably restrained at its end remote from the stem from rotation about its longitudinal axis.

What is claimed is:

l. A dolphin structure adapted to absorb horizontal loading forces without adverse force transfer to the bottom comprising:

a vertical stem member of selected resiliency extending from above the water surface to the bottom for intercepting horizontal loading forces;

at least two laterally extending members affixed to the base of said vertical stem member to provide therewith at least three points of support for said structure and to distribute and absorb the horizontal loading forces received at the upper end of the vertical stem member by reason of their weight, length and resiliency, said laterally extending members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces;

support means on the bottom positioned at each of the end points of support for said structure for supporting said dolphin structure above the bottom surface.

said support means disposed one adjacent the end of each of the laterally extending members and one at the base of the vertical member; and means secured to each of said support means for maintaining said structure upon said support means and adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in horizontal loading applied at the Water surface to said vertical member. 2. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include a centrally disposed concave depression in the top of each support means and an appendage attached to the bottom of each laterally extending memher.

said appendage having a convex undersurface adapted to substantially conform to said concave depression, said concave and convex surfaces substantially in register when said structure is at rest. 3. The dolphin structure of claim 2 and further including vertically extending means attached to said support means for permitting limited lateral movement of said laterally extending members of said support means.

4. The dolphin structure of claim 3 and further including restraining means connected across said vertically extending means for limiting the lift-off of said laterally extending members from said support means.

5. The dolphin structure of claim 1 wherein the laterally extending members are at least three in number and the support means are disposed one adjacent the end of each of the laterally extending members;

means including vertically disposed guide means secured to each of said support means for maintain ing said structure upon said support means and for directing the downward movement of the ends of said laterally extending members after lift-off; and

transverse stop means secured to said laterally extending members disposed intermediate respective pairs of said guide means when said structure is at rest.

6. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral and upward movement of the respective laterally extending members and means at the base of said vertical member for limiting lateral movement thereof in directions included in the angular sector between said laterally extending members.

7. A dolphin structure comprising:

a vertical member for receiving horizontal loading forces;

a footing for supporting said structure on the seabed,

said footing including at least two members secured to and diverging laterally from the base of said vertical member;

substantially all of the horizontal loading forces received by said vertical member being counterbalanced by the weight. length and resiliency of said dolphin structure members,

said laterallydiverging members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces;

support means on the bottom for supporting said dolphin structure above the bottom surface, said laterally extending members being two in number and said support means disposed one adjacent the end of each of said laterally extending members and one at the base of the vertical member; and means secured to each of said support means for maintaining said structure upon said support means, said means adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in the horizontal loading applied at the water surface to said vertical member. 8. The dolphin structure of claim 1 wherein the laterally extending members are at least three in number and the support means are disposed one adjacent the end of each of the laterally extending members;

means secured to each of said support means for maintaining said structure upon said support means, i said means for maintaining said structure including vertically disposed guide means straddling said laterally extending members for directing the downward movement of the ends of said laterally extending members after lift-off; and transversc'stop means secured to said laterally extending members and disposed intermediate respective pairs of said guide means when said struc ture is at rest.

9. The dolphin structure of claim 8 wherein said means for maintaining said structure upon said support means include a centrally disposed concave depression in the top of each support means and an appendage attached to the bottom of each laterally extending member, i

said appendage having a convex undersurface adapted to, substantially conform to said concave depression,

said concave and convex surfaces substantially in register when said structure is at rest.

10. The dolphin structure of claim 9 and further including vertically extending means attached to said support means and straddling said laterally extending members for limiting the lateral movement of said members on said support means.

y l l. The dolphin structure of claim 10 and further including restraining means connected across said vertically extending means for limiting the lift-off of said laterally extending members from said support means.

12. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral at least two laterally extending support members of selected length affixed to the base of said vertical stem member to support said stem member on the surface of the bottom and provide stability against upset of said dolphin,

said laterally extending members and said vertical stem member distributing and absorbing the h0r izontal loading forces received by said stem member,

said laterally extending members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces and absorbing said forces by rea son of their weight, length and resiliency;

pad means on the bottom positioned at each of the end points of support of said laterally extending members for providing prepared surface areasfor supporting said laterally extending members,

said laterally extending members two in number and said support means disposed one adjacent the end of each of the laterally extending members and one at the base of the vertical member;

and

means secured to each of said support means for maintaining said 7 structure upon said support means,

said means for maintaining said structure upon said support means adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in the horizontal loading applied at the water surface to said vertical member.

14. The structure as defined in claim 13 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral and upward movement of the respective laterally extending members and means at the base of said vertical member for limiting lateral movement thereof in directions included in the angular sector between said laterally extending members. 

1. A dolphin structure adapted to absorb horizontal loading forces without adverse force transfer to the bottom comprising: a vertical stem member of selected resiliency extending from above the water surface to the bottom for intercepting horizontal loading forces; at least two laterally extending members affixed to the base of said vertical stem member to provide therewith at least three points of support for said structure and to distribute and absorb the horizontal loading forces received at the upper end of the vertical stem member by reason of their weight, length and resiliency, said laterally extending members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces; support means on the bottom positioned at each of the end points of support for said structure for supporting said dolphin structure above the bottom surface, said support means disposed one adjacent the end of each of the laterally extending members and one at the base of the vertical member; and means secured to each of said support means for maintaining said structure upon said support means and adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in horizontal loading applied at the water surface to said vertical member.
 2. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include a centrally disposed concave depression in the top of each support means and an appendage attached to the bottom of each laterally extending member, said appendage having a convex undersurface adapted to substantially conform to said concave depression, said concave and convex surfaces substantially in register when said structure is at rest.
 3. The dolphin structure of claim 2 and further including vertically extending means attached to said support means for permitting limited lateral movement of said laterally extending members of said support means.
 4. The dolphin structure of claim 3 and further including restraining means connected across said vertically extending means for limiting the lift-off of said laterally extending members from said support means.
 5. The dolphin structure of claim 1 wherein the laterally extending members are at least three in number and the support means are disposed one adjacent the end of each of the laterally extending members; means including vertically disposed guide means secured to each of said support means for maintaining said structure upon said support means and for directing the downward movement of the ends of said laterally extending members after lift-off; and transverse stop means secured to said laterally extending members disposed intermediate respective pairs of said guide means when said structure is at rest.
 6. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral and upward movement of the respective laterally extending members and means at the base of said vertical member for limiting lateral movement thereof in directions included in the angular sector between said laterally extending members.
 7. A dolphin structure comprising: a vertical member for receiving horizontal loading forces; a footing for supporting said structure on the seabed, said footing including at least two members securEd to and diverging laterally from the base of said vertical member; substantially all of the horizontal loading forces received by said vertical member being counterbalanced by the weight, length and resiliency of said dolphin structure members, said laterally diverging members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces; support means on the bottom for supporting said dolphin structure above the bottom surface, said laterally extending members being two in number and said support means disposed one adjacent the end of each of said laterally extending members and one at the base of the vertical member; and means secured to each of said support means for maintaining said structure upon said support means, said means adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in the horizontal loading applied at the water surface to said vertical member.
 8. The dolphin structure of claim 1 wherein the laterally extending members are at least three in number and the support means are disposed one adjacent the end of each of the laterally extending members; means secured to each of said support means for maintaining said structure upon said support means, said means for maintaining said structure including vertically disposed guide means straddling said laterally extending members for directing the downward movement of the ends of said laterally extending members after lift-off; and transverse stop means secured to said laterally extending members and disposed intermediate respective pairs of said guide means when said structure is at rest.
 9. The dolphin structure of claim 8 wherein said means for maintaining said structure upon said support means include a centrally disposed concave depression in the top of each support means and an appendage attached to the bottom of each laterally extending member, said appendage having a convex undersurface adapted to substantially conform to said concave depression, said concave and convex surfaces substantially in register when said structure is at rest.
 10. The dolphin structure of claim 9 and further including vertically extending means attached to said support means and straddling said laterally extending members for limiting the lateral movement of said members on said support means.
 11. The dolphin structure of claim 10 and further including restraining means connected across said vertically extending means for limiting the lift-off of said laterally extending members from said support means.
 12. The dolphin structure of claim 1 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral and upward movement of the respective laterally extending members and means at the base of said vertical member for limiting lateral movement thereof in directions included in the angular sector between said laterally extending members.
 13. A dolphin structure adapted to be supported solely upon the seabed or the bottom of a body of fresh water and to absorb horizontal loading forces without adverse force transfer to the bottom comprising: a vertical stem member of selected resiliency extending from above the water surface to the bottom for intercepting horizontal loading forces; at least two laterally extending support members of selected length affixed to the base of said vertical stem member to support said stem member on the surface of the bottom and provide stability against upset of said dolphin, said laterally extending members and said vertical stem member distributing and absorbing the horizontal loading forces received by said stem member, said laterally extending members varied in length and angular separation in relation to the direction and magnitude of anticipated horizontal loading forces and absorbing said forces by reason of their weight, length and resiliency; pad means on the bottom positioned at each of the end points of support of said laterally extending members for providing prepared surface areas for supporting said laterally extending members, said laterally extending members two in number and said support means disposed one adjacent the end of each of the laterally extending members and one at the base of the vertical member; and means secured to each of said support means for maintaining said structure upon said support means, said means for maintaining said structure upon said support means adapted to allow selected freedom of movement of the base of said vertical member and said laterally extending members in response to changes in the horizontal loading applied at the water surface to said vertical member.
 14. The structure as defined in claim 13 wherein said means for maintaining said structure upon said support means include means on said support means remote from the base of the vertical member for limiting lateral and upward movement of the respective laterally extending members and means at the base of said vertical member for limiting lateral movement thereof in directions included in the angular sector between said laterally extending members. 